I’ve gone ahead and put together what I have in mind for the VGA cable with R/G/B out.
I was thinking that, if I am running output to Banana terminals for wire antennas, I would just design 75 Ohm filters to hard connect inside the little Aluminium box between the 3 RCA socket block and Bananas. See the first pic. It is going ahead smoothly despite requiring quite a bit of accurate hole drilling and hole matching with the 3 RCA socket board.I think it will be very neat.
Secondly, I have designed three Constant K 750 Ohm filters that are dual band:
60m & 40m, 30m & 20m and 17m & 12m. Whilst I have not built these all yet, I have modelled them on LTSpice and they look to have very suitable performance and all are using standard component values or a minimum combination thereof.
Here's the box showing how the VGA connector to RCA lead is used.
75 Ohm 60 and 40m
I’m stopping at 12m now as I am not sure of the wave from a 17m or 12m Weaver generation, but the multiples of 48K, QRG and Sample rate seem to be close.
You can contact Ross at any of the following callsigns @amsat.org: VK1UN, VK8UN, 6O0O, T61AA, EX1UN.
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